#include <iostream>
#include <cstring>
using namespace std;

const int N = 10e5 + 3;

int h[N], e[N], ne[N], idx;

void insert(int x) {
    int k = (x % N + N) % N;
    e[idx] = x;
    ne[idx] = h[k];
    h[k] = idx++;
}

bool find(int x) {
    int k = (x % N + N) % N;
    for (int i = h[k]; i != -1; i = ne[i])
        if (e[i] == x) return true;
    return false;
}

int main() {
    int n;
    scanf("%d", &n);
    memset(h, -1, sizeof(h));
    while (n--) {
        char op[2];
        int x;
        scanf("%s%d", op, &x);
        if (*op == 'I') insert(x);
        else {
            if (find(x)) puts("Yes");
            else puts("No");
        }
    }
    return 0;
}